Bayan Shireh Formation

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Bayan Shireh Formation
Stratigraphic range: Late Cretaceous (Cenomanian-Santonian?)
Type Geological formation
Sub-units "Sheeregeen Gashoon" beds (upper Bayan Shireh)
Location
Region Asia
Country Mongolia

The Bayan Shireh Formation (also known as Bayanshiree Svita or the Baynshirenskaya Formation) is a geological formation in Burkhant, Mongolia, that dates to the late Cretaceous period. The exact age is uncertain, with two competing hypotheses; based on comparisons with other formations, the Bayan Shireh fauna seems to correspond best with the Turonian through early Campanian stages of the Late Cretaceous, about 93 to 80 million years ago.[1] However, examination of the magnetostratigraphy of the formation seems to confirm that the entire Bayan Shireh lies within the Cretaceous Long Normal, which lasted only until the end of the Santonian stage, giving a possible Cenomanian through Santonian age, or between 98 and 83 million years ago.[2] The fauna of this formation is similar to the nearby Iren Dabasu Formation.

Fauna[edit]

Theropod dinosaurs[edit]

Theropods reported from the Bayan Shireh Formation
Genus Species Location Stratigraphic Position Material Notes Images

Achillobator

"Partial skull and fragmentary postcrania."[3]

a giant dromaeosaur

Alectrosaurus

a tyrannosaur. Also present in the Iren Dabasu Formation

Enigmosaurus

"Incompletely preserved pelvis."[4]

a therizinosaur

Erlikosaurus

"Skull, pes, [and a] fragmentary postcranium."[4]

a therizinosaur

Garudimimus

"Skull with associated incomplete postcranium."[5]

an ornithomimosaur

Segnosaurus

"[Three] specimens, including mandible pelvis, hindlimb, scapulocoracoid, incomplete forelimb, [and] fragmentary vertebrae."[4]

a therizinosaur

Ornithischian dinosaurs[edit]

Ornithischians reported from the Bayan Shireh Formation
Genus Species Location Stratigraphic Position Material Notes Images

Amtosaurus

A. magnus

"Fragmentary skull."[6]

Graciliceratops

Sheeregeen Gashoon beds

"Partial skull, skeleton."[7]

A primitive ceratopsian.

Maleevus

Sheeregeen Gashoon beds

an ankylosaur

Microceratus

Sheeregeen Gashoon beds

A primitive ceratopsian, also present in the Minhe Formation

Talarurus

"More than [five] specimens, including [two] partial skulls, nearly complete skeleton, osteoderms."[8]

an ankylosaur

Tsagantegia

"Skull."[8]

an ankylosaur

See also[edit]

References[edit]

  1. ^ Jerzykiewicz, T. and Russell, D.A. (1991). "Late Mesozoic stratigraphy and vertebrates of the Gobi Basin." Cretaceous Research, 12(4): 345-377.
  2. ^ Hicks, J.F., Brinkman, D.L., Nichols, D.J., and Watabe, M. (1999). "Paleomagnetic and palynological analyses of Albian to Santonian strata at Bayn Shireh, Burkhant, and Khuren Dukh, eastern Gobi Desert, Mongolia." Cretaceous Research, 20(6): 829-850.
  3. ^ "Table 10.1," in Weishampel, et al. (2004). Page 198.
  4. ^ a b c "Table 7.1," in Weishampel, et al. (2004). Page 152.
  5. ^ "Table 6.1," in Weishampel, et al. (2004). Page 138.
  6. ^ "Table 17.1," in Weishampel, et al. (2004). Page 367.
  7. ^ "Table 22.1," in Weishampel, et al. (2004). Page 480.
  8. ^ a b "Table 17.1," in Weishampel, et al. (2004). Page 364.